DTC 11

Transponder Communication System or Radio Interference of Encrypted Code

Ignition Key Ring Antenna Circuit:

CIRCUIT OPERATION
The ignition key is powered by the ignition key ring antenna, and sends an encrypted code. The ignition key ring antenna receives the encrypted code, and determines whether the ignition key is a registered key or not.

DTC SET CONDITION
- If the engine is started while several ignition keys are in the vicinity, interference between the different keys may occur, which will cause this code to be generated.
- The encrypted code of the transponder is not sent to the immobilizer-ECU immediately after the ignition switch is turned to "ON" position.

NOTE: DTC 11 is always output together with MFI system DTC P0513.

TROUBLESHOOTING HINTS
- Radio interference of encrypted code
- Malfunction of transponder
- Malfunction of ignition key ring antenna
- Malfunction of immobilizer-ECU
- Damaged wiring harness of connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicles Communication Interface (V.C.I.)
- MB991827: MUT-III USB Cable
- MB991911: Main Harness B (Vehicles without CAN communication system)

STEP 1. Check there is another key near the ignition key.

Q: Is there any other key near the ignition key?

YES: Move the other key well away from key being used. Confirm that diagnostic trouble code 11 is not output.

NO: Go to Step 2.

STEP 2. Check that the engine starts using the spare ignition key which encrypted code has been registered.

Q: Does the engine start using the spare ignition key which encrypted code has been registered?

YES: Replace the ignition key that does not work. Then register the password (secret code) and encrypted code (Refer to How to Register Encrypted Code). Confirm that diagnostic trouble code 11 is not output.

NO: Go to Step 3.

STEP 3. Recheck for diagnosis trouble code.




1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Use scan tool MB991958 to check immobilizer system diagnostic trouble codes.
4. Turn the ignition switch to "LOCK" (OFF) position.
5. Disconnect scan tool MB991958.

Q: Which DTC is output, DTC 11 or 12?

DTC12 is output: Refer to DTC 12.

DTC11 is output: Go to Step 4.

STEP 4. Check the ignition key ring antenna by backprobing.




1. Disconnect column switch connector C-88, and measure at the wiring device side.




2. Measure the resistance value between terminal number 3 and terminal number 7 by backprobing.
- The measured value should be 2 ohm or less.

Q: Does the measured resistance value correspond with this range?

YES: Go to Step 5.

NO: Replace the ignition key ring antenna. Confirm that diagnostic trouble code 11 is not output.







STEP 5. Check immobilizer-ECU connector C-79 and ignition key ring antenna connector C-88 for damage.

Q: Are immobilizer-ECU connector C-79 and ignition key ring antenna connector C-88 in good condition?

YES: Go to Step 6.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. Confirm that diagnostic trouble code 11 is not output.







STEP 6. Check the wiring harness between immobilizer-ECU connector C-79 (terminal 10 and 11) and ignition key ring antenna connector C-88 (terminal 3 and 7).

Q: Are the wiring harness between immobilizer-ECU connector C-79 (terminal 10 and 11) and ignition key ring antenna connector C-88 (terminal 3 and 7) in good condition?

YES: Replace the immobilizer-ECU. Then register the password (secret code) and encrypted code (Refer to How to Register Encrypted Code). Confirm that diagnostic trouble code 11 is not output.

NO: Repair the wiring harness. Confirm that diagnostic trouble code 11 is not output.